As his run for re-election starts to gear up, Gov. Cuomo is in surprisingly weak shape. With a huge war chest in a heavily Democratic state, he’s still the odds-on favorite — but he’s suddenly looking a lot more vulnerable.

Here are 10 big reasons why the governor has to worry.

He burned Mayor de Blasio. Sure, he made himself look good to centrist voters by humiliating the new herald of progressivism on both pre-K and charter schools. But he also earned a black eye with the left — and made an enemy of the mayor, who after all is the top politician in a city where Cuomo needs a lot of votes come November.

He’s annoyed the public-employee unions. He tightened the state school-aid spigot and put in his property-tax cap, making it harder for teachers locals across New York to win higher pay. Then he pushed for test-based teacher evaluations, anathema to the unions. (Yes, the scheme never had real teeth, but unions can’t stand the precedent.) And he topped it all off with his embrace of charters — which the unions, not without reason, see as a naked bid for fat hedge-fund donations. Other unions feel burned because he forced modest contracts on most state-employee unions and won minor public-pension reforms. They won’t go to war on him for that — but why should they lift a finger to help?Now his sudden rush to win some union friends is getting ugly. Few voters will notice or care that the Transit Workers Union contract pays for raises by adding hundreds of millions to the MTA’s long-term liabilities — but they can understand a $6 million TWU slush fund.

His robotic pretense that he’s still “studying” fracking after three-plus years is an oozing political sore. It tells people leading hardscrabble lives all across Upstate that he cares more about millionaires and special interests than he does about them — and doesn’t even have the guts to be upfront about it. The hypocrisy of his pose is so rank, it’s hard to see how anyone can trust his word on anything, public or private.

He backs the Independent Democratic Caucus, which sides with the Republicans to control the majority-Democratic state Senate. The black and Hispanic Democrats shut out by that scheme know who’s really to blame.

He played the anti-corruption card for short-term gain. He’s shutting down his Moreland Commission, with nary a corrupt scalp collected, now that the Legislature’s gone his way this year. Cuomo hasn’t moved to clean up the Albany sewer, just sprayed a little air freshener. Better hope Preet Bharara doesn’t indict any more state senators before November. (Not a good bet.)

He burned the cardinal, too. When Cuomo jumped in on charters, he used chits that could’ve gone to pass the education-tax-credit bill. The archbishop of New York plainly thought he had a firm promise the bill would become law — and (as President Obama learned on abortion and ObamaCare) the cardinal has ways of getting back at deal-breakers.

His gimmicky “reforms” insult those they’re supposed to help. Has “Start Up New York” fostered a single startup? Are you going to change your vote thanks to a $500 “rebate” check on your $15,000 property-tax bill? Oh, and the public-campaign-finance nuts rightly aren’t buying his “demonstration” run of their system in the state comptroller’s race.

He keeps slapping the other two top state officerholders. The latest: Comptroller Tom di Napoli didn’t even get a heads-up that his race was going to be that public-campaign-finance “demonstration,” while Attorney General Eric Schneiderman had control of the hundreds of millions in the JP Morgan mortgage settlement yanked away. Di Napoli can embarrass the governor just by running a few numbers honestly. Schneiderman has a legal role in Cuomo’s now-squelched Moreland Commission — wonder if his office is behind any of those embarrassing leaks about how political it was?

He’s facing a surprisingly united GOP opposition. Sure, some of the most “transactional” Republicans in state politics will endorse him — but that highlights Cuomo’s air-freshener approach to Albany corruption.

His Republican opponent is the party’s best natural statewide candidate in living memory. Sure, Rob Astorino is pro-life and anti-anti-gun. But he’s relaxed and charming where Cuomo is tense and brittle. And he’s won twice in Democratic, swing-county Westchester, running up a solid record of trimming government, cutting taxes and fostering new jobs. That’s going to matter a lot to any voters who happen to focus on jobs. Astorino’s still a long-shot to win — but an ever-better bet to hold the governor below 55 percent. That would be a huge defeat for a guy who wants a blowout to bolster his chances for a presidential run in 2016.